"Mozilla's VP of Technical Strategy, Mike Shaver has rejected Microsoft's criticism of WebGL in which it said it would not implement the 3D graphics standard because of security issues in the design. Shaver says that "there is no question that the web needs 3D capabilities" to enable developers to create "advanced visualisations, games or new user interfaces" and points at Molehill (Adobe's 3D for Flash) and Microsoft's Silverlight 3D which are offering just those capabilities." One discussion of Microsofts WebGL criticism can be found here.

The second article lists the issues that Microsoft has with WebGL and I think they are valid concerns.

The Mozilla argument ignores the issues presented by Microsoft, and instead tries to reframe the discussion about whether the web should get 3d acceleration - which is not the issue that Microsoft is talking about.

The issue is how should the web get 3d acceleration and the questions/issues MS brings up about exposure of present drivers is a valid issue.